Questions tagged [beam]
Questions about the theory and applications of structural elements designed to resist bending.
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What is the equivalent rotational/angular stiffness of a beam
I'm trying to model a larger system and working through a conceptual issue. I'm familiar with the concept of expressing the stiffness of a beam as an equivalent spring stiffness like in the image ...
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Post and steel rope framework for grape vine
I am planning to build a framework to support a grape vine above a patio. Ideally I would like to use steel rope to provide this framework, rather than a full timber frame.
Diagram attached.
There is ...
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Deflection of a log splitter beam
I'm designing a machine that can be simplified as a log splitter. It will have a long, central beam that will resist both the forces of a force pushing out and the moment that will be caused by the ...
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Finding the bending moment diagram for an indeterminate continuous beam
In a recent lecture, we had the following example of an indeterminate continuous beam where we must find the redundant support reaction at $A$:
This was found by removing the support at $A$, and then ...
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Stress and Displacement of Cantilever Plate with a Uniform Load
Does any one happen to know of any resources that describe the stress and displacement of a uniformly distributed load in the direction perpendicular to the length direction of a plate analytically? I ...
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Cantilever Beam Deflection under Plane strain
I have a university code that calculates the maximum deflection of cantilever beam of length, $L$ subjected to a point load, $P$ on its free end. The software assumes plane strain conditions. I ...
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How do I calculate kg/m for 5 boards sitting on 3 beams
I'm new to this, thank you for your patience,
I have some wooden boards that each weigh 5.5 kg with dimensions of 120 cm * 60 cm
I also have some wooden beams with dimensions of 3 meters length and 10 ...
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Is the maximum bending moment of a fixed end beam always at end?
Mathematically, we can see that with downward loads only (only upward loads at the ends), the maximum bending moment for a fixed end beam of span $L$ either occurs at $x=0$, $x=L$, or where the shear ...
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Bending analysis of beams with varying cross section
All problems I solved in MoM class regarding beam bending involved a beam with continuous cross section. But is the process the same for a beam with varying cross section? For 'same process' I mean ...
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Composite Beam Theory - Calculating torsion and beam deflection of a composite beam made up of a pipe inside a pipe
I am trying to calculate two things. First the beam deflection of my model after bending and second angle of twist after applying torque.
My model is composed of two tubes (cylindrical hollow beams). ...
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Compound angle for support tri-beam / double knee brace
I'm trying to determine the most structurally sound way to construct a support beam for a serious treehouse. There are four options I've mocked up below - the first two are individual knee brace ...
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Maximum Deflection for simply supported beam under arbitrary triangular loading
I am trying to get the:
maximum deflection
location of maximum deflection
deflection at any point
For a beam under an arbitrary triangular load (i.e. a, b, c, and w can vary). I tried to solve this ...
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My solution of this deflection of beam problem not matching with the book solution
Here is the problem and it's solution done in book - https://imgur.com/a/DRS7OvN
Here is my solution - https://imgur.com/a/Yd9JGuC
The book solution has 1/384wL^4 term but I am getting 1/128wL^4. ...
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How to convert multiple point loads to uniformly distributed load
So I am working on a project with variables on how many point loads may be applied over a single span.
Both ends are fixed, this is a constant.
For example, I may have a beam which is 6m in overall ...
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Timoshenko Fixed Fixed Total Beam Deflection
I am trying to solve a problem where there is a fixed-fixed (clamped-clamped) beam with a point load in the middle (at L/2). The L/H is less then the 10 required for normal beam bending analysis and ...
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How to find the location on the 2-support beam where the deflection will be biggest?
Consider the uniform indeterminate beam as shown above. This beam is to be subjected to a single, 80N point load (acting down ) somewhere along its length.
What is the procedure (i.e steps and logic) ...
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Does the inertia of a beam section include the material density?
Sorry but I'm a little rusty. When solving a beam of any type of section, must the density be included in the moment of inertia of the section?
For example, if I see Navier's formula, I would say ...
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Get Node Numbers to Variable
I am using Andys APDL.
I want to create Beam Element by entering Node numbers.
Nodes numbers selection is through option “by location“
Then I don’t know how use them in element creation command i.e. E,...
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deflection of mild steel hollow tube beam
I am trying to compute the deflection of a hollow tube of mild steel, and my computation seems to give radically different results than a couple of online calculators. Apparently one is in error.
The ...
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Horizontal "pinching" force of an arch with applied moment
I have some Shape Memory Alloy wire programmed to curl from a straight beam into a circle. The force this generates is approximated as a uniform distributed bending moment along the length of the wire....
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Beam load - bending design value of southern GC yellow pine for treehouse beam span
I'm looking to build a treehouse and wanting to ensure the support beams can carry a sufficient load over an 11-ft span. Based on page 78 (aka 83) of https://awc.org/wp-content/uploads/2021/12/AWC-...
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Why is this bridge thickest above the support pillars instead of the mid-span where the bending stress is highest?
Why is a bridge designed like this?
The depth of the section at pillars is more than the depth at middle.
If I model this as a simply supported beam having load at mid span then the bending moment ...
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How to design the thickness and diameter of a cantilever beam in bending for both composites and metals?
The goal is to find the optimum values of the diameter and the thickness of the circular cross-section of a cantilevered beam in bending, with the lowest weight (cross-sectional area). The main ...
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Any way to approximate effect of two point loads with just one?
Imagine a 3D problem where the goal is to calculate the max. cantilever beam deflection. There are 4 equal point loads A, B,C,D separated equally from the beam's major axis.
Is there a way to ...
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Max bending moment estimate
Context: I study aerodynamics and want to design and build an RC wing to put the theory I learned into practice. The essence of the theory I learned is: Given some mass of wing building material, how ...
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Magnitude of shear stress on beam element
In a previous question, the existence of a horizontal shear stress in a cantilevered I-beam with one free end was resolved. Here I'd like to explore the magnitude of the shear stress. Consider an I-...
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Direction of shear in beam cross section - how to understand the convention
In an I-beam, the shear flow is usually shown drawn as on the left, not as drawn on the right. I do not understand why. I do understand:
The total horizontal shear force must be zero, consistent with ...
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How can I understand shear flow in a beam cross section?
I am trying to understand shear flow and I am just not getting it. For example, one of the problems in Beer has an I-beam and there is both a horizontal and vertical force acting on it. So it has ...
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Are there disadvantages to using a single multispan beam, vs separate simple beams, for materials that tolerate tension as well as compression?
Suppose the following beam situation within a mundane building (viewed from above). Assume vibration and torsion aren't issues. Suppose we have a choice to span a gap in 2 different ways:
(Grey = ...
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Does the corbel angle govern in this scenario? If not, how is load spreading allowed for, when a load is supported by a wall on a beam
The following outline is inspired by something I noticed today and couldn't figure out.
It shows what I guess is a fairly common generic situation - an upper floor masonry partition wall supported by ...
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Analysing a multispan determinate beam by separating it into spans
Say we have the following indeterminate beam:
We can make it determinate by adding a pin at B, and then adding back the bending moment at B which was destroyed by the pin:
My lecture handouts then ...
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Composite Cantilever Beam Analysis
I'm trying to solve this composite cantilever beam for deflection analysis. How should I proceed? I'm not from mechanical background.
The connection between the elements is strong enough that the ...
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Simply supported beam with a truss
i am trying to find out the best way to approach a design task for a plane wing with a truss support. i am treating the wing as a simply supported beam but i have no idea how to incorporate the truss ...
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Rigidity and bending moment
When a beam which is fixed at one end and free at the other, is acted upon by a load P, the beam bends and we get a bending moment at every cross section of the beam. This bending moment can be ...
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What's the best shape (solid of revolution) for a cantilever beam to carry a point load at the free end?
How should you change the diameter/radius (while keeping constant overall volume) of the cross-section along the length of a round cantilever beam so that you minimise deflection with concentrated ...
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Maximum deflection in the beam
Consider a simply supported beam, acted upon by a concentrated load P as shown
By applying the method of successive integration, i.e. by using the differential equation
$$EI \frac{d^2v}{dx^2} = M$$
...
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Forces supporting a beam
I've been struggling with this engineering problem. The forces I've got are Frb=2.08kN, Fray=15.12kN, and Frax=3kN. Before i give in my calculations I need to do a check if they are correct or not ...
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Why the vertical shear stress in the flange neglected?
Consider a thin walled I section beam. At some intermediate c/s the shear force is V. The shear stress direction in flanges and web will be as shown.
The textbook says that, the vertical shear ...
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How exactly the beam is twisting?
Consider an I section beam shown below, which is unsymmetric about the x-y plane.
I apply a load P, at the centroid of this section. The textbook I follow, says that the member will twist apart from ...
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First moment of area about the neutral axis
Consider a homogeneous beam with a rectangular c/s, its neutral axis will be at equal distances from the top and bottom edges.
The first moment of the entire area about the NA will be zero, since we ...
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Should the stiffness of this cantilever beam be different for these two conditions?
So, I was just doing some Finite Element Analysis (FEA) to figure out what would be the effect on the stiffness of a cantilever beam if another beam is attached to it on its free end.
Below shows the ...
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How are beams arranged in a continuous concrete beam structure?
I am posed with this problem, where I am tasked to design multiple structural beams supporting a concrete slab. As a disclaimer, this problem is merely an exercise instead of a homework or a test, and ...
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Why in a rectangular cross section beam the shear stresses are parallel to the height throughout the surface?
Consider a beam with a rectangular c/s subjected to some arbitrary loading. At any cross section the shear force is V. This shear force is the resultant of all the internal resistive forces which act ...
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Are there any stresses on this plane in a beam?
Consider a cantilever beam with a point load at its free end. If we cut the beam through a plane as shown (in which the load lies), to divide the beam into two parts, and if we isolate individual ...
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Direction of Shear Stress on the periphery of a circular section beam
The Question is from shear stresses in beams
Consider a beam made of circular cross section, in which at any cross section the shear force is V.
The textbook I'm following states that -
When a beam ...
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How is the limit state EQU used in Eurocode?
Quote from here:
Limit state EQU, dealing with static equilibrium, is defined as: Loss of static equilibrium of the structure... considered as a rigid body, where minor variations in the [actions or ...
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Due to what reason are the beams getting elongated?
I was studying about shear stresses in beams, where one of the ways the textbook tried explaining intuitively the presence of shear stresses in beams was:
Source : Mechanics of Materials, R.C. ...
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Proving the advantage of a composite beam
The textbook that I'm following for studying bending stresses in beams, states that - "Engineers purposely design beams in this manner (composite manner) in order to develop a more efficient ...
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Determining the ratio of bending moments in parts of a composite beam
Consider a composite beam formed by sandwiching a wood beam between two steel plates, whose cross section is shown.
Say the beam is loaded by some arbitrary loading, due to which at any cross section ...
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Beam of uniform strength
Generally, for a given loading condition, the bending moment in a beam varies throughout its length due to which the maximum normal/bending stress at every section is different. For a given allowable ...
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